Related papers: X-ray emission from early-type galaxies
Galactic X-ray emission is a manifestation of various high-energy phenomena and processes. The brightest X-ray sources are typically accretion-powered objects: active galactic nuclei and low- or high-mass X-ray binaries. Such objects with…
Star-forming regions have been the targets of X-ray observations since the dawn of satellite X-ray astronomy. The increase in sensitivity and/or spatial resolution offered by XMM-Newton and Chandra allows a dramatic improvement, both…
Quasars at z>4 provide direct information on the first massive structures to form in the Universe. Recent ground-based optical surveys (e.g., the Sloan Digital Sky Survey) have discovered large numbers of high-redshift quasars, increasing…
Observational programmes currently underway with both Chandra and XMM-Newton are set to revolutionize our view of our own Galaxy. This is fortunate since the X-ray band can provide crucial diagnostics in the quest to understand the…
The features and make up of the population of X-ray sources in Galactic star clusters reflect the properties of the underlying stellar environment. Cluster age, mass, stellar encounter rate, binary frequency, metallicity, and maybe other…
In the last eight years, the Chandra and XMM-Newton satellites changed significantly our view of X-ray clusters of galaxies. In particular, several complex phenomena have been directly observed: interactions between cluster galaxies and the…
A decade of X-ray stellar observations with Chandra and XMM-Newton has led to significant advances in our understanding of the physical processes at work in hot (magnetized) plasmas in stars and their immediate environment, providing new…
Observations with powerful X-ray telescopes, such as XMM-Newton and Chandra, significantly advance our understanding of massive stars. Nearly all early-type stars are X-ray sources. Studies of their X-ray emission provide important…
X-ray studies of high-redshift (z > 4) active galaxies have advanced substantially over the past few years, largely due to results from the new generation of X-ray observatories. As of this writing X-ray emission has been detected from…
Massive halos of hot plasma exist around some, but not all elliptical galaxies. There is evidence that this is related to the age of the galaxy. In this paper new X-ray observations are presented for three early-type galaxies that show…
The origin of the X-ray emission from the central region of the Galaxy has remained a mystery, despite extensive study over the past two decades. A fundamental question is the relative contribution of the point-source and diffuse components…
To test the cooling flow model of early-type galaxies, we obtained a complete magnitude-limited sample of 34 early-type galaxies, observed with the PSPC and HRI on ROSAT. The X-ray to optical distribution of galaxies implies a lower…
The Galactic plane is a strong hard x-ray emitter and the emission forms a narrow continuous ridge. The currently known hard x-ray sources are far too few to explain the ridge x-ray emission, and the fundamental question as to whether the…
Many X-ray observations of GigaHertz Peaked Spectrum and Compact Steep Spectrum sources have been made with Chandra X-ray Observatory and XMM-Newton Observatory over the last few years. The X-ray spectra contribute the important information…
Statistical properties of X-ray luminosity and temperature are studied for 52 early-type galaxies based on the ROSAT PSPC data. All of the X-ray luminous galaxies show largely extended emission with a radius of a few times of 10$r_e$, while…
The Galactic Center is a prominent source in X-rays and gamma-rays and the study of its high-energy emission is crucial in understanding the physical phenomena taking place in its dense and extreme environment, phenomena that are possibly…
We report on the first results of a multi-wavelength approach to test the hypothesis that the X-ray emission from intermediate-mass stars is generated by late-type magnetically active companions. Our high spatial resolution observations of…
In the era of Chandra and XMM-Newton, the detection (or nondetection) of diffuse and/or point-like X-ray sources within planetary nebulae (PNe) yields important, unique insight into PN shaping processes. Diffuse X-ray sources, whether due…
Observations of the Ly-alpha forest at z~3 reveal an average metallicity Z~0.01 Z_solar. The high-redshift supernovae that polluted the IGM also accelerated relativistic electrons. Since the energy density of the CMB scales as (1+z)^4, at…
X-ray astronomy is closely related to the study of black hole sources. The discovery that some unseen objects, more massive than any degenerate star, emit huge amounts of X-rays helped accept the concept that back holes are present in X-ray…